This invention relates to char-forming aromatic polymer compositions containing ester of trifluoromethanesulfonic acid.
Polymer compositions having reduced propensity to burn have generally been prepared by incorporating therein halogenated materials. Such materials are thought to operate to inhibit combustion in the gaseous phase adjacent to the polymer surface by the release of halogen-containing vapors at elevated temperatures. See for example, U.S. Pat. Nos. 3,700,957; 3,773,825; 3,775,367; and 3,804,885. Such halogenated materials are hereinafter also referred to as conventional combustion inhibitors. However, these halogenated materials often have a plasticizing effect on the polymer composition, particularly at the elevated temperatures accompanying a fire. Therefore the presence of such materials often deleteriously affects the structural integrity of polymeric articles under such conditions and can significantly increase the dripping of molten polymer.
The effectiveness of halogenated combustion-inhibiting agents can be enhanced by the formation of a rigid char barrier that prevents or at least impedes the migration of combustible fuel to the point of combustion. Such a char barrier serves to enhance the structural integrity of the burning polymeric article, to inhibit dripping of molten polymer and to thermally insulate the unburned portion from the heat generated by combustion. The formation of char also often reduces the smoke emission of burning polymer compositions. U.S. Pat. No. 3,810,862 describes char-forming, flame-retardant polyolefin compositions.
In view of the advantages of char formation upon combustion of polymer compositions and in view of the general unavailability of char-forming aromatic polymer compositions, it would be highly desirable to provide such char-forming polymer compositions.